TY - JOUR
TI - Effect of working fluids and internal diameters on thermal performance of vertical and horizontal closed-loop pulsating heat pipes with multiple heat sources
AU - Kammuang-Lue Niti
AU - Sakulchangsatjatai Phrut
AU - Terdtoon Pradit
JN - Thermal Science
PY - 2016
VL - 20
IS - 1
SP - 77
EP - 87
PT - Article
AB - Some electrical applications have a number of heat sources. The closed-loop  pulsating heat pipe (CLPHP) is applied to transfer heat from these devices.  Since the CLPHP primarily transfers heat by means of the working fluid’s  phase change in a capillary tube, the thermal performance of the CLPHP  significantly depends on the working fluid type and the tube’s internal  diameter. In order to provide the fundamental information for manufacturers  of heat exchangers, this study on the effect of working fluids and internal  diameters has been conducted. Three electrical plate heaters were installed  on the CLPHP as the heat sources. The experiments were conducted by varying  the working fluid to be R123, ethanol, and water, and the internal diameter  to be 1.0 mm, 1.5 mm, and 2.0 mm. For each set of the same working fluid and  internal diameter, the input heat fluxes of the heat sources were also made  to vary within six different patterns. It can be concluded that when the  latent heat of evaporation increases - in the case of vertical CLPHP - and  when the dynamic viscosity of the liquid increases - in the case of  horizontal CLPHP - the thermal performance decreases. Moreover, when the  internal diameter increases, the thermal performance increases for both of  vertical and horizontal CLPHPs.